Conventionally, the most relevant art of the preferred embodiments of this invention is shown in FIGS. 1, 2, 3 and 4. As shown, the prior art comprises a lower housing 51, a motor 2 mounted in the lower housing 51, a lower belt wheel 5 mounted on the driving shaft of the motor 2, an upper housing 52 right above the lower housing 51, particularly right above the position where the motor 2 is mounted, a transmission shaft 8 mounted partially in the upper housing 52 by means of two bearings 20, an upper belt wheel 7 mounted on one end of the transmission shaft 8, a transmission belt 6 connecting the upper belt wheel 7 and the lower belt wheel 5, a cylinder 1 having a neck portion 22 at one end, the cylinder 1 being fixed onto one end of the upper housing 52 with the neck portion 22, a cylindrical cooling chamber 16 mounted on the inner wall of the cylinder 1, a plurality of cooling compartments 16a, 16b, 16c, 16d, 16e and 16f provided in the cylindrical cooling chamber 16, a water inlet 13 provided on the outer end of the cylinder 1, a water outlet 17 on the inner end of the cylinder 1, a refined liquid material chamber 11 in the neck portion 22, a refined liquid material outlet 12 provided on the lower portion of the refined liquid material chamber 11, a lubricant seal 21 mounted onto the outer end of the neck portion 22 to define one wall of the refined liquid material chamber 11, a gap 10 between the inner end wall of the neck portion 22 and the transmission shaft 8 which extends outside of the upper housing 52, a plurality of blades 9 mounted on the outer end of the transmission shaft 8 which extends inside of the cylinder 1, a pump 3 mounted opposite to the motor 2 in the lower housing 51, a liquid material inlet 4 connecting the pump 3 and the cylinder 1, a plurality of glass beads 19 provided inside of the cylinder 1, a liquid material supplying tank (not given a reference number), a refined liquid material collecting tank (not given a reference number) and a power supply (not given a reference number) connected to the pump 3 and the motor 2.
According to the above disclosed prior art, the liquid material such as paint, ink, dying material, medicine, etc., is driven by the pump 3 through the liquid material inlet 4 into the cylinder 1 and simultaneously the motor 2 rotates the lower belt wheel 5. Further, the upper belt wheel 7 driven by the transmission belt 6 will rotate the transmission shaft 8. The blades 9 rotation will force the glass beads 19 to grind the liquid material. The refined liquid material will flow through the gap 10 into the refined liquid material chamber 11 and further flow out of the refined liquid material outlet 12 into the liquid material collecting tank. Simultaneously, the cooling water flows through the water inlet 13 into the cooling compartments 16a, 16b, 16c, 16d, 16e and 16f and further flows out of the water outlet 17 to prevent high temperature caused by the grinding effect from affecting the quality of the liquid material.
However, the above disclosed prior art bears the following defects:
(1) FIG. 3 shows an enlarged view of the area identified in FIG. 2 by reference character B between the end wall of the neck portion 22 and the transmission shaft 8. FIG. 4 is a front view of FIG. 3. As shown in FIGS. 3 and 4, an eccentric misalignment between the shaft 8 and the gap 10 caused during manufacturing or assembly will cause any glass beads 19 entering a larger clearance of the gap to be ground into power at a smaller clearance of the gap. The undesired powdered glass beads will mix with the refined liquid material and lower the quality of the refined liquid material at the outlet 12.
(2) As shown in FIG. 2, the lubricant seal 21 of the prior art is in contact with the transmission shaft 8. The abrasion thus caused is great. The lubricant seal 21 must be reviewed frequently. Otherwise, the lubricant will leak into the refined liquid material to spoil the quality.
(3) As shown in FIG. 2, the cooling chamber 16 is further divided into a plurality of cooling compartments. Thus, each cooling compartment, in turn, is required to be filled up with water before the water is allowed to flow into the next cooling compartment. This causes the cooling water to linger, and to mix with the heated water. As a result, the heat can not be effectively cooled down.